Download
1 / 12
120 likes | 133 Views
Dive into the fascinating world of phylogeny and the tree of life in AP Biology with topics ranging from taxonomy and binomial nomenclature to cladistic analysis and molecular cladograms. Explore how phylogenetic trees are constructed, the significance of shared primitive and derived characters, and the importance of parsimony in developing phylogenetic hypotheses. Discover the complexities of molecular cladograms and the role of outgroup comparison in evolutionary studies.
E N D
Phylogeny and the Tree of Life AP Biology Crosby High School
Taxonomy • Binomial Nomenclature • Genus specium • Hierarchical Classification • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species • PhyloCode?
Terminology • Dichotomies • Sister Taxa • Rooted • Basal Taxon • Polytomy
Cladistic Analysis • Clade • Cladogram: Phylogenetic diagram • Dichotomies • Monophyletic (“single tribe”)
Constructing a Cladogram • Created from Homology not Analogy • More similar Homologies are more closely related • The more complex two structures are the more likely they are homologous • Shared Primitive Character: common to more inclusive taxon • Mammal backbone • Shared Derived Character: unique to defined taxon • Mammal hair
Outgroup Comparison • Outgroup: Very distant from studied Organisms • Ingroup: Studied Organisms • Which one of these things is not like the other? • Ancestor more recent, not species
Molecular Cladograms • Constructed from differences in DNA sequences • rRNA used for taxa that diverged from 100s to millions of years ago • mtDNA used for more recent divergences • Insertions and Deletions must be accounted for
Parsimony • Keep it simple • Requires the least amount of changes or evolutions to occur
Phylogenetic Trees are Hypotheses • They are a guess • Most parsimonious = most accepted • Unless evidence proves otherwise • The same evolutionary event occuring more than once in unrelated cases is unlikely • Strongest hypotheses are supported by morph., molec., and fossil record
